To increase the integration and performance of modern integrated circuits, the circuits are also produced on a plurality of substrates which are then arranged in a compact stack form. For this, the circuitry often requires a through hole through a substrate or a through contact, with an individual substrate being part of a substrate stack. The stack may require such electrical through contacts in order to allow signal or else power connection paths from one substrate to another substrate or else from the circuit.
In this context, the through contact, and also the electronically functionalized elements in the substrate, are subject to a compulsion toward miniaturization in order to meet modern requirements in terms of integration and performance. To produce miniaturized through contacts, through holes with diameters in the region of a few microns and below are produced before the individual substrates are stacked, and through appropriate arrangement and orientation in the individual substrates these through holes then form a continuous channel in the substrate stack. The channel can then be filled with a conductive material in order to form the through contact. In this case, the conventional filling of such channels is often done using sputtering or plating methods.
When the liquid conductive material is introduced by capillary forces, one is reliant on the inherent properties of the channel, of the through holes, and of the properties of the channel walls, which are stipulated by the quantity of material and the time in which the material penetrates the channel. When using capillary forces as a driving force, certain restrictions may apply regarding the diameters of the channels, the depth or length of the channels and the materials used. The time which is required in order to introduce the relevant quantity of material into the channel can also be long in the case of given channel dimensions and hence can counteract an effective production process. Often, capillary forces also may not allow reliable filling of the channels with a well-defined and reproducible quantity of material.